The Rides to Lake Silberneherze level RS-EX-5, Spiral, Challenge Mode, cleared using only Welfare operators.
I had a really tough time figuring out how to manage the Delegation Centurion Champions. Eventually, I got Lou Xiauhei, Folinic, and Heavyrain to deal with them at the very left side of the map.
For the main entrance to my gate, it was a bit chaotic. I had to keep the Boom Canisters away from my operators so they wouldn't kill them when they went Boom. So, I piled on the ranged operators, focussing more on physical damage. Lots of my operators died, so I just kept replacing them. This particular clear was a bit lucky, in that I had to panic place Whislash and then Puzzle when Czerny was killed. In my practice runs, Czerny never died. Still it miraculously worked out.
Welfare operators are as defined at:
arknights.wiki...
wiki/Operator/Welfare.
Comments and advice are always appreciated.